Launching a secure kernel in a multiprocessor system

ABSTRACT

In one embodiment of the present invention, a method includes verifying an initiating logical processor of a system; validating a trusted agent with the initiating logical processor if the initiating logical processor is verified; and launching the trusted agent on a plurality of processors of the system if the trusted agent is validated. After execution of such a trusted agent, a secure kernel may then be launched, in certain embodiments. The system may be a multiprocessor server system having a partially or fully connected topology with arbitrary point-to-point interconnects, for example.

This application is a division of U.S. patent application Ser. No.10/859,897 filed Jun. 3, 2004 entitled “LAUNCHING A SECURE KERNEL IN AMULTIPROCESSOR SYSTEM,” the content of which is hereby incorporated byreference.

BACKGROUND

The present invention relates to computer systems and more particularlyto initiating secure operations therein.

A link-based system topology may include multiple nodes connected bypoint-to-point links. The topology may not be fully connected; that is,a given node may not be directly connected to all other nodes, but anynode may reach any other node via multiple links, based on configuredrouting mechanisms. As examples, the nodes may be a processor, aninput/output (I/O) hub, or another such device.

At the outset of system operation, processor hardware is trusted tobehave as specified, and link mechanisms are trusted to deliverlink-layer messages sent by hardware from one link controller to anotherlink controller. Further, the link mechanisms provide trustedinformation about the hardware components at each end of a link.Similarly, hardware mechanisms of the I/O hubs are trusted to behave asspecified.

In certain implementations, a given protocol running on a system fabricmay be used to access memory and maintain a coherent appearance andbehavior of the totality of memory as a single physical address space,although separate physical memories may exist. However, this coherentbehavior depends on address decoding and routing mechanisms that areconfigured by untrusted software. Therefore, such a protocol cannot betrusted to access memory correctly until the configuration has beenvalidated. In particular, it cannot be trusted to be free ofconfiguration errors and improper operations, such as memory aliases, orusing the same physical address with different mappings. Thus a needexists to initiate a trusted environment in such a system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a flow diagram of a method in accordance with one embodimentof the present invention.

FIG. 1B is a continuation of the flow diagram of FIG. 1A.

FIG. 2 is a block diagram of a system in accordance with one embodimentof the present invention.

FIG. 3 is a block diagram of a spanning tree constructed in accordancewith an embodiment of the present invention.

FIG. 4 is a block diagram of a trusted hardware link in accordance withan embodiment of the present invention.

FIG. 5 is a timing diagram of a secure launch in accordance with oneembodiment of the present invention as viewed by an initiating logicalprocessor.

FIG. 6 is a timing diagram of a secure launch in accordance with oneembodiment of the present invention as viewed by a responding logicalprocessor.

DETAILED DESCRIPTION

In various embodiments, a secure kernel may be securely launched thatruns on all processors in a system topology. Further, an identity of thesecure kernel may be measured and recorded in a secure manner, alongwith one or more software agents used in the launch process. In suchmanner, a chain of transitive trust rooted in hardware that is used tolaunch the secure kernel may be recorded.

In certain embodiments, the trusted hardware may include a master I/Ohub to which a master trusted platform module (TPM) is attached. A(non-secure) operating system (OS) may have knowledge of this aspect ofthe topology. Further, a trusted software agent may be executed so thatits execution cannot be tampered with in any way.

A user or system administrator may desire to load a secure kernel in asystem. As referred to herein, the term “secure” refers to thecapability to later inspect the system and determine whether a givenkernel was loaded. Further, the user or third party may furtherdetermine whether the kernel was loaded into a secure memoryenvironment. Accordingly, in one embodiment, an outside agent mayestablish trust or decide to trust the kernel contained within thesecure environment by being provided the capability to inspect softwarein the secure environment. In one embodiment, rather than expose theentire region to inspection, a cryptographic hash value (e.g., asoftware identification value) representing the secure memory region maybe inspected. In one embodiment, the digitally signed secure softwareidentification value may be stored in hardware accessible by the outsideagent.

Referring to FIG. 1A, shown is a flow diagram of a method of launching asecure kernel on a multiprocessor system in accordance with oneembodiment of the present invention. As shown in FIG. 1A, method 100 maybegin by loading a trusted agent and a secure kernel into memory (block110). In one embodiment, a non-trusted OS may load the trusted agent andthe secure kernel into a secure region of system memory. The trustedagent and the secure kernel may be stored in a mass storage device, suchas a disk drive, and may be loaded into system memory that may beaccessed by the multiple processors of the system. In addition, the OSmay construct page tables to address the secure kernel and trustedagent. The address and length of these page tables may be stored inspecial locations in a master I/O hub of the system, in one embodiment.The OS may also store a public key used to authenticate the module. Inone embodiment, the trusted agent may be secure authenticated code thatis used to validate a configuration of the system, and morespecifically, a memory configuration of the system. The trusted agentmay be further used to initiate execution of the secure kernel.

Next, the OS may issue a secure launch on an initiating logicalprocessor (ILP) (block 120). Such a secure launch may be a secured enter(SENTER) instruction to initiate a secure enter. Execution of the SENTERinstruction may cause the ILP to issue special bus messages both withinits socket and other processor sockets, and then wait considerable timeintervals for subsequent system actions.

In one embodiment, the ILP may be directly coupled to the master I/Ohub, which in turn may be directly coupled to a master TPM. In such anembodiment, the ILP may validate that it has a trusted path to themaster TPM. For example, trusted link parameters in the ILP's socket maybe examined. Such a path may be a trusted hardware path that does notneed to be initialized by firmware or software. At this point inexecution of the method, in an embodiment in which the ILP is part of amultiprocessor socket, the ILP may also cause other logical processors(OLPs) in the socket to be halted.

Next, the ILP may construct a spanning tree (block 130). Such a spanningtree may be constructed in accordance with a desired algorithm. Thespanning tree may be used to identify all other nodes of the system inrelation to the ILP node in a plurality of levels of a tree structure,with the ILP acting as the root of the tree. Nodes directly connected tothe ILP may be second level nodes, nodes directly connected to thesesecond level nodes may be third level nodes and so forth. Such aspanning tree may be used to validate the proper configuration of thesystem and to enable routing of link-based messages to the differentnodes. Only trusted hardware and links may be used to construct thespanning tree. In certain embodiments, the spanning tree may provide atrusted broadcast mechanism whereby the ILP can send a message to everyprocessor socket, a means for each processor socket to respond to thebroadcast message and for these responses to be summarized as they passup the tree back to the ILP, and a barrier mechanism to ensure that allprocessor sockets have reached a known state before the ILP proceedswith a next broadcast message.

Still referring to FIG. 1A, at block 140 a secure launch message may besent to the other sockets on the spanning tree. In one embodiment, suchmessages may be sent using a spanning tree protocol that sends messagesfrom the root level to the next level (i.e., to downlink nodes), whichin turn sends messages to the next lowest level, and so forth. Inresponse, each level may send response packets back up to itstransmitting level (i.e., to uplink nodes). Accordingly, when all thenodes receive the message and respond appropriately, a final summaryresponse packet may be transmitted back to the root node. At this pointin execution of the method, a responding logical processor (RLP) on eachof the sockets may cause the OLPs on the socket to be halted.

Referring now to FIG. 1B, when the ILP receives the summary responseindicating that all other nodes have properly received and responded tothe SENTER instruction, the ILP may validate the trusted agent (block150). Such validation may include, for example, performing a hashcomputation and comparing the result to a previously stored hash value.Such validation information may then be sent to the RLPs (block 160).The RLPs may each individually validate that it can access the trustedagent in the protected memory location and validate the trusted agent(block 170).

When validation summary responses are received by the ILP for each ofthe RLPs, the ILP may then control execution of the trusted agent on allsockets of the system (block 180). For example, in one embodiment, theILP may use barrier mechanisms to initiate portions of the trustedagent, wait for an indication from each socket that it has performedthat portion of the trusted agent, and then proceed on to the nextportion. Such indications may be sent using the spanning tree protocoldiscussed above.

The hardware thus uses the spanning tree to launch the identical trustedagent on every processor socket. The trusted agent may execute on everyprocessor socket concurrently in a coordinated single instructionmultiple data (SIMD)-type execution. These trusted agent executionsconspire to completely validate the memory configuration of thetopology, using the spanning tree to coordinate and communicate with theILP. When the trusted agent successfully validates the configuration,the trusted agent execution on the ILP may validate the page tables usedto address the secure kernel, compute the hash of the kernel, and recordthe hash in the master TPM.

At the conclusion of the execution of the trusted agent, the ILP maylaunch the secure kernel (block 190). At such time, the secure kerneltakes over system operation, and may execute in accordance with the codetherein (block 195). For example, the secure kernel may be executedacross all sockets of the system.

Referring now to FIG. 2, shown is a block diagram of a system inaccordance with one embodiment of the present invention. As shown inFIG. 2, system 200 may be a multiprocessor system having an arbitrary,partially connected point-to-point architecture. That is, certain nodesof the system 200 may be directly coupled together, while other nodesmay communicate via an intermediate node coupled therebetween. In otherembodiments, system 200 may have a fully connected topology. In oneembodiment, system 200 may be a simultaneous multiprocessing (SMP)server computer, although the scope of the present invention is not solimited.

That is, while shown in FIG. 2 as a server platform, it is to beunderstood that in other embodiments, a system may be any one of adesired desktop, mobile, server or other such platform. In certainembodiments, interconnections between different components of FIG. 2 maybe point-to-point interconnects that provide for coherent shared memorywithin system 200, and in one such embodiment the interconnects andprotocols used to communicate therebetween may form a common systeminterface (CSI). In such manner, multiple processors, memories, andother components of system 200 may coherently interface with each other.

In the embodiment of FIG. 2, all components of system 200 maycollectively form a coherent system. Such a coherent system mayaccommodate coherent transactions without any ordering between channelsthrough which transactions flow. While discussed herein as a coherentsystem, it is to be understood that both coherent and non-coherenttransactions may be passed through and acted upon by components withinthe system. For example, a region of one, some, or all memoriesassociated with system 200 may be reserved for non-coherenttransactions. Also, it is to be understood that embodiments of thepresent invention are not limited to coherent systems.

As shown in FIG. 2, a first processor socket 210 may include a pluralityof processing cores 212 a, 212 b, 212 c, and 212 d. While shown in theembodiment of FIG. 2 as including four such processing cores, it is tobe understood that in other embodiments, processor sockets may includemore or fewer such cores. As further shown in FIG. 2, the processorcores may be coupled together via a bus or ring 215. In certainembodiments, such as an embodiment in accordance with a CSI protocol,the processor socket may also include additional logic functionality,such as memory controller functions, and CSI packet generation androuting mechanisms.

As an example, shown in FIG. 2 within processor socket 210 is logicfunctionality 216, which may include memory controller and other logicfunctionality. Logic functionality 216 may associate a node identifier(NID) with the processor socket. As shown in FIG. 2, processor socket210 may have anode identifier of one, indicating in one embodiment thatit is the initiating logical processor. Logic functionality 216 mayinclude a source address decoder that maps addresses to correspondingnodes (e.g., NIDs) for all items in a physical memory map. If configuredproperly, each processor socket may include logic functionality having asource address decoder that corresponds the same addresses to the samenodes. The NIDs, in one embodiment, may be assigned by untrustedfirmware upon system initialization, and accordingly, may not be unique.Thus in certain embodiments, a trusted agent may be used to determinewhether the NIDs for each of the nodes are in fact unique. In certainembodiments, logic functionality 216 may also include a target addressdecoder that maps addresses to physical memory, for example, physicalmemory directly connected to a given processor socket.

A memory 218 may be directly coupled to processor socket 210. Whilememory 218 may be directly coupled to processor socket 210, it is to beunderstood that in various embodiments, any of the processor socketswithin system 200 may access memory 218. Memory 218 may interface withprocessor socket 210 using memory controller functionality within logicfunctionality 216. Further, while not shown in FIG. 2, it is to beunderstood that each processor socket may have one or more memoriesassociated therewith. While each socket may have a physical memorydirectly coupled thereto, additional memory elements, such as caches,may be associated with the individual processing cores within theprocessor sockets. In one embodiment, all memories within a system maybe addressed as a single physical address space, although multiple suchmemories may exist, each directly connected to a different processorsocket.

As further shown in FIG. 2, processor socket 210 is directly connectedto processor socket 220, processor socket 250, and processor socket 260.Furthermore, processor socket 210 is directly connected to a master I/Ohub 290, which in turn is directly coupled to a master TPM 292. Whilenot discussed in detail herein, processor sockets 230, 240, 270 and 280(and sockets 220, 250 and 260) may have similar processing cores, buses,rings and logic functionality as discussed with regard to processorsocket 210. Finally, further shown in FIG. 2 is a second I/O hub 295,which is directly connected to processor sockets 250, 260, 270 and 280.

I/O hubs 290 and 295 may each include a plurality of ports to interfacewith I/O devices coupled thereto. For example, in certain embodiments,such I/O devices may be devices in accordance with one or more busschemes. In one embodiment, such I/O devices may be Peripheral ComponentInterconnect (PCI) Express™ devices in accordance with the PeripheralComponent Interconnect Express Base Specification Version 1.0a(published July 2002). Master TPM 292 may be a trusted platform modulein accordance with the Trusted Computing Platform Alliance (TCPA) MainSpecification Version 1.1b (published Feb. 22, 2002). Master TPM 292 mayprotect data related to creating and maintaining a secure operatingenvironment. In a particular embodiment, master TPM 292 may include keysfor specific encryption, decryption and/or validation processes. MasterTPM 292 may also include storage space to hold a digest value and otherinformation to be used in the secure environment. In one embodiment, thestorage space in master TPM 292 may include non-volatile memory (e.g.,flash memory) to retain its contents in the event of power loss.

While shown in the embodiment of FIG. 2 as including four or five directconnections for each processor socket, other embodiments may have moreor fewer direct connections between different sockets. More so, it is tobe understood that in different embodiments more or fewer sockets may bepresent, each having differing numbers of cores and differing amounts oflogic functionality. For example, a single processor system may beimplemented having a single I/O hub and associated I/O devices coupledthereto. Alternately, a multiprocessor system having a different numberof processors (such as 4, 8, 16, or 32) may be implemented, and anappropriate number of I/O hubs and other components may be coupledthereto. Any such platform topologies may take advantage ofpoint-to-point interconnections to provide for coherency within acoherent portion of the system, and also permit non-coherentpeer-to-peer transactions between I/O devices coupled thereto.Additionally, in certain embodiments, additional components may bepresent in system 200 such as crossbars, routers and the like.

Referring now to FIG. 3, shown is a block diagram of a spanning tree inaccordance with one embodiment of the present invention. As shown inFIG. 3, spanning tree 300 may be a graphical representation of aspanning tree constructed by an ILP. More specifically, spanning tree300 corresponds to a spanning tree for system 200 of FIG. 2 in whichprocessor socket 210 includes the ILP. Note that each node of thespanning tree has a node identifier corresponding to the node identifierof the matching processor socket of FIG. 2. As shown in FIG. 3, the rootlevel node 310 has a node identifier of 1, corresponding to processorsocket 210 of FIG. 2. The level two nodes include the nodes that aredirectly coupled to processor socket 210. Specifically, as shown in FIG.3, the level two nodes include nodes 315, 320, 325, and 330, eachcorresponding to the nodes of system 200 directly coupled to processorsocket 210, namely processor sockets 220, 250 and 260, and master I/Ohub 290.

A third level of nodes includes nodes 335, 340 and 350. Each of thesenodes corresponds to a node directly connected to a second level node.For example, node 335 (e.g., corresponding to I/O hub 295) is directlycoupled to processor socket 250; node 340 (i.e., corresponding toprocessor socket 270) is directly coupled to processor socket 260; andnode 350 (i.e., corresponding to processor software 230) is directlycoupled to processor socket 220. Finally, a fourth level of nodesincludes nodes 355 and 360, both of which are directly coupled to athird level node, namely node 340.

Thus a spanning tree identifies the number of participating socketswithin a system. Each socket in the system (except the root socket) mayhave one link identified as an uplink. Broadcast messages generated bythe ILP may be received by an RLP from its uplink. Further, all sockets,except for those that are leafs (e.g., the fourth level nodes of FIG. 3)may have links identified as downlinks. Each socket may propagatebroadcast messages to their downlinks. In certain embodiments, a lookuptable or other data structure corresponding to the graphicalrepresentation shown in FIG. 3 may be stored in a memory associated withprocessor socket 210 for use by the ILP.

Thus at the end of construction of the spanning tree, the spanning treeincludes information regarding the number of nodes and the levelsthereof. At the conclusion of spanning tree enumeration, uniqueidentifiers may be assigned to each of the nodes, and a count of nodesbelow a given node may also be determined and stored. Thus as shown inFIG. 3, in addition to the node identifiers (also shown in FIG. 2) foreach of the nodes, an additional spanning tree unique identifier may bepresent (e.g., node ID one has a spanning tree identifier of one,whereas node ID 5 has a spanning tree identifier of two).

Referring now to FIG. 4, shown is a block diagram of trusted linkhardware in accordance with one embodiment of the present invention.Such trusted link hardware may be used to provide a trusted hardwarelink within a processor socket for use prior to completion of executionof a trusted agent. Such a trusted hardware link may be trusted, as nofirmware or software is needed for operation and transmission ofmessages along the link. Trusted link hardware 455 a and 455 b may becontained within a processor socket (i.e., sockets 410 a and 410 b).While two such sockets are shown in FIG. 4, socket 410 a and itscomponents will be discussed herein. As shown in FIG. 4, hardware link455 a may be coupled between a processor core 420 a and a linkcontroller 450 a. Using trusted hardware link 455 a, trusted linkmessages may be sent and received from core 420 a without relying onsoftware or firmware.

In contrast, for normal system messaging and packet transmissions,link-based messages travel to/from core 420 a via a bus or ring 425 athrough a core interface 430 a and a protocol engine 435 a. In oneembodiment, protocol engine 435 a may be a CSI protocol engine to formatdata and messages into CSI packets. Further, a bus 440 a couplesprotocol engine 435 a through a crossbar 445 a. From there, data andmessages may be sent to other nodes, memory associated with theprocessor socket, to link controller 450 a, or other desired locations.

Because the components including core interface 430 a, protocol engine435 a, and crossbar 445 a are set up by untrusted firmware, this pathmay not provide a non-spoofable access path prior to complete executionof a trusted agent. Thus in various embodiments, hardware link 455 a mayprovide a non-spoofable access path between core 420 a and linkcontroller 450 a, which is particularly suited for use prior tovalidation of the system by a trusted agent. For example, prior tovalidation, link controllers, such as link controllers 450 a and 450 bmay be used to generate link messages using a special instruction from acore. A receiving link controller may thus capture link message contentand make it directly available to a processor core via a trustedhardware link, such as trusted hardware link 455 a. In certainembodiments, an event mechanism from a link controller to a processorcore may occur so that microcode in the core may be informed of thearrival of new link messages on the trusted hardware link. During linkinitialization, information regarding neighboring nodes may be capturedby a link controller and may be available to both protocol engine andthe processor core. In such embodiments, such information may include anode type and a node identifier for the neighboring nodes.

As further shown in FIG. 4, corresponding components to those discussedabove with regard to processor socket 410 a may be found in processorsocket 410 b. Furthermore, a trusted link between the two processorsmaybe effected via a hardware link 460 coupled between link controller450 a and link controller 450 b. This trusted link may be used to sendlink-based messages between processor sockets prior to validation of thesystem by a trusted agent.

Referring now to FIG. 5, shown is a timing diagram of a secure launch inaccordance with one embodiment of the present invention, as viewed bythe ILP. As shown in FIG. 5, secure launch 500 begins by loading atrusted agent and a secure kernel into memory (segment 502). Asdiscussed above, in one embodiment a non-trusted OS may perform suchloading operations. Then a SENTER instruction may be sent to a processorsocket including a desired ILP (segment 504). For example, such aninstruction may be issued by a non-trusted OS.

When the ILP receives the SENTER instruction, it may issue a similarinstruction to other logical processors within its socket and also toother processor sockets, and more specifically to a responding logicalprocessor (RLP), of which there may be one in each processor socket(time 505). The determination of which logical processor may be the ILPand/or RLP may vary in different embodiments, and may be based on asoftware or firmware determination. For example, in one embodiment theILP may be chosen by an OS. Further, the RLP within other processorsockets may be chosen by all the logical processors in a given socket.At time 510, the ILP may verify that it is directly connected to themaster I/O hub. Then at time 515, the ILP may broadcast a SENTER busmessage to the OLPs within its socket, and each OLP may respond to theSENTER instruction (time 520).

At this time, a SENTER local event (segment 522) may begin. At time 525,each OLP may issue an acknowledgment (ACK) and enter a wait state. Sucha wait state may be maintained by the OLPs until later commanded toleave the wait state by the ILP.

Then a SENTER global instruction phase (segment 528) may be entered.First, the ILP may send a message seeking acknowledgement (ACK) from thenodes within the system. When ACKs are received by the ILP, it may senda continue instruction (time 530). At this time, the ILP may construct aspanning tree.

While construction of a spanning tree may take different forms, in oneembodiment a spanning tree may be constructed by sending pulses that arelink-level messages broadcast down the tree to a next lower level, andreceiving returns, which are link-level messages containing accumulatedresults back up the tree. In such manner, each RLP that receives a pulsemessage may forward it to its downlinks, and receive return messagestherefrom. The spanning tree link-based message that is sent may causeeach socket to set a level for each of the sockets. Then, spanning treeenumeration may occur in which a unique identifier may be assigned toeach node. Accordingly, upon completion of the spanning tree, eachsocket is assigned a unique identifier and a level, further indicatingits relative location with respect to the ILP and uplink and downlinkconnections to/from the socket.

Upon validation and completion of the spanning tree, the ILP may sendthe SENTER instruction to all other processor sockets (time 535). Next,the ILP may merge a summary response received from nodes on the spanningtree (time 540). An algorithm over the tree verifies that the softwareconfiguration of the topology has given each node a unique identifierthat may be used in a routing protocol of the system.

Then the ILP may measure (i.e., compute the hash) and authenticate(i.e., verify a signature) the trusted agent that it finds at thedesignated address in the master I/O hub and broadcast the hash value,base address and length of the trusted agent, and a hash of the publickey used to verify the signature to the other processor sockets (time550). Such a broadcast may occur using the spanning tree protocol. Whenthe other sockets validate the trusted agent, they will send responsemessages that are then merged by the ILP at time 555. If every socketsends a positive response, the ILP may load, record the hash of thetrusted agent (e.g., in the master TPM) and launch the trusted agent attime 560. If one or more sockets fail to respond positively, the securelaunch may be terminated, in certain embodiments. In the embodimentshown in FIG. 5, the trusted agent may be a secure trusted agent (e.g.,entitled SINIT-AC, for a secure initialization-authenticated code),although the scope of the present invention is not so limited.

Then the trusted agent may be executed (segment 572). In one embodiment,execution of the trusted agent may occur in a loosely lock-step SIMDexecution. That is, the same trusted agent may execute on all sockets,synchronized at particular barriers within the code. For example, theILP may issue a broadcast message including an opcode and data on alllinks. Each RLP may get the data and forward the message to itsdownlinks, if any, and process the data. If the RLP is a leaf, it maysend a response message back up to its uplink. If the RLP is anintermediate node, it may wait for all responses from its downlinks,summarize all response data using opcodes, and send a summarizedresponse to its uplink. When finally the ILP obtains a summarizedresponse from all other sockets, execution may continue in similarmanner to a next barrier position.

During execution, the trusted agent may validate the local configurationand source address decoder on each processor socket (time 570). Further,the trusted agent may validate the uniqueness of each of the nodeidentifiers for each processor socket (time 575). For example, thetrusted agent may cause the source address decoders to be sent to theILP (time 580). Then the ILP may merge and analyze the results of acomparison of source address decoders (time 585). Then, the trustedagent may terminate by validating, loading, recording and launching thesecure kernel (time 590). Such validation information (e.g., a hashvalue) may be stored in a master TPM, in certain embodiments. In oneembodiment, the secure kernel may be a secure virtual machine monitor(SVMM), although the scope of the present invention is not so limited.

Still referring to FIG. 5, monitor initialization (segment 592) maycause the ILP to wake up all processor cores in all sockets with aspecial instruction to cause all processors to exit their waiting state.Thus at segment 596 all monitors join and at time 598 all processorcores are participating and secure kernel operations may begin (segment599).

Referring now to FIG. 6, shown is a timing diagram of a secure launch inaccordance with one embodiment of the present invention. Morespecifically, FIG. 6 shows the timing of a secure launch as viewed by aresponding logical processor (RLP). Thus the secure launch 600 seen inFIG. 6 corresponds closely to that occurring in the timing diagram ofFIG. 5. First, a SENTER doorbell event occurs (segment 604). During suchan event, the RLP is interrupted by the SENTER doorbell instruction fromthe ILP (time 605). Then at time 610, the RLP sends a SENTER downlinkmessage to its downlink nodes (if any). At time 615, the RLP broadcaststhe SENTER message to all processors (i.e., OLP's) within its socket.Each of the other logical processors in the socket may respond to theSENTER cycle (time 620). Then a SENTER local event (segment 622) occurs,in which each OLP issues an ACK back to the ILP and the OLPs enter await state (at time 625).

Then at segment 628, a SENTER doorbell global event occurs. When allACKs from downlink nodes are received by the RLP, it sends a continuemessage to the ILP (time 630). The RLP merges such continue messages attime 635. Then at time 640, the RLP may receive validation informationfrom the ILP. In one embodiment, the ILP may send information regardingthe trusted agent hash value, base, size, and public key hash. Furtherat this time, the RLP may forward this information to its downlinkednodes. At time 645, the RLP may compare the hash received to its hash ofthe trusted agent.

At time 650, the RLP receives validation messages from its downstreamnodes and merges those results. Also, the RLP sends a summary responseup through its upstream node to the ILP. Then based on informationreceived from the ILP, the RLP loads, authenticates, checks thesignature of the trusted agent, and launches the trusted agent (time655).

If all processor sockets reach this point, the trusted agent executes(segment 672). Specifically, the trusted agent validates the localconfiguration and node IDs of each processor socket (time 660), andchecks and validates the source address decoder within the sockets(times 665 and 670). The RLP may receive results of this validation fromdownlink sockets and merge and send the results up to its uplinkprocessor or the ILP (time 675). Then the RLP socket enters a specialwait state (at time 680).

At this point, the secure kernel is launched, first on the ILP socket(segment 692). Then at time 685, the secure kernel on the ILP wakes upall processor cores on all sockets with a special wake instruction. Atthis time, the secure kernel may continue its execution on some or allof the processors of the system. For example, following the securelaunch, a virtual machine environment may be created in which the SVMMmay operate as the most privileged code within the system, and may beused to permit or deny direct access to certain system resources by theOS or applications within virtual machines.

In such manner, embodiments of the present invention may record andlaunch a trusted secure kernel on an arbitrarily complex server hardwaretopology that has been configured by untrusted software and firmware.The kernel may then proceed to construct, record and attest to a trustedserver execution environment. Further, in certain embodiments, a trustedagent may be executed in SIMD-style on all processor sockets in a servertopology, and by using a trusted barrier/broadcast mechanism, theconfiguration of an arbitrarily complex server topology may bevalidated, and by transitive trust from hardware through the trustedagent, a secure environment can be recorded and launched.

Embodiments may be implemented in code and may be stored on a storagemedium having stored thereon instructions which can be used to program acomputer system to perform the instructions. The storage medium mayinclude, but is not limited to, any type of disk including floppy disks,optical disks, compact disk read-only memories (CD-ROMs), compact diskrewritables (CD-RWs), and magneto-optical disks, semiconductor devicessuch as read-only memories (ROMs), random access memories (RAMs),erasable programmable read-only memories (EPROMs), flash memories,electrically erasable programmable read-only memories (EEPROMs),magnetic or optical cards, or any type of media suitable for storingelectronic instructions.

While the present invention has been described with respect to a limitednumber of embodiments, those skilled in the art will appreciate numerousmodifications and variations therefrom. It is intended that the appendedclaims cover all such modifications and variations as fall within thetrue spirit and scope of this present invention.

1. A method comprising: constructing a spanning tree across a pluralityof processors of a system using an initiating logical processor; andlaunching a trusted agent on the plurality of processors using thespanning tree.
 2. The method of claim 1, further comprising executingthe trusted agent on the plurality of processors.
 3. The method of claim1, further comprising loading a secure kernel into a memory of thesystem using a non-secure operating system.
 4. The method of claim 3,further comprising storing information regarding the secure kernel andthe trusted agent in a master hub agent of the system.
 5. The method ofclaim 1, further comprising enumerating each of the plurality ofprocessors with a unique identifier in the spanning tree.
 6. The methodof claim 5, further comprising associating a number of downlink nodescoupled to each of the plurality of processors with the uniqueidentifier.
 7. The method of claim 1, wherein constructing the spanningtree comprises broadcasting a first message to directly connected nodesand receiving return messages from the directly connected nodes.
 8. Themethod of claim 7, further comprising forwarding the first message fromthe directly connected nodes to downlink nodes directly connectedthereto.
 9. The method of claim 1, further comprising selecting theinitiating logical processor as a root of the spanning tree.
 10. Anarticle comprising a machine-accessible medium including instructionsthat when executed cause a system to: construct a spanning tree across aplurality of processors of the system using an initiating logicalprocessor; and launch a trusted agent on the plurality of processorsusing the spanning tree.
 11. The article of claim 10, further comprisinginstructions that when executed enable the system to execute the trustedagent on the plurality of processors.
 12. The article of claim 11,further comprising instructions that when executed enable the system toload a secure kernel into a memory of the system using a non-secureoperating system.
 13. The article of claim 12, further comprisinginstructions that when executed enable the system to store informationregarding the secure kernel and the trusted agent in a master hub agentof the system.
 14. The article of claim 10, further comprisinginstructions that when executed enable the system to enumerate each ofthe plurality of processors with a unique identifier in the spanningtree.
 15. The article of claim 14, further comprising instructions thatwhen executed enable the system to associate a number of downlink nodescoupled to each of the plurality of processors with the uniqueidentifier.
 16. The article of claim 15, further comprising instructionsthat when executed enable the system to broadcast a first message todirectly connected nodes, forward the first message from the directlyconnected nodes to downlink nodes directly connected thereto, andreceive return messages from the directly connected nodes.
 17. Thearticle of claim 10, further comprising instructions that when executedenable the system to select the initiating logical processor as a rootof the spanning tree.
 18. A system comprising: a plurality ofprocessors, wherein one of the plurality of processors comprises aninitiating logical processor; a storage medium coupled to the pluralityof processors including instructions that enable the system to constructa spanning tree across the plurality of processors using the initiatinglogical processor, and launch a trusted agent on the plurality ofprocessors using the spanning tree.
 19. The system of claim 18, whereinthe spanning tree is to identify a number of participating sockets inthe system, wherein each socket has a first link identified as an uplinkand a second link identified as a downlink, wherein leaf sockets do notinclude downlinks.
 20. The system of claim 19, wherein the spanning treeis to associate a node identifier and a spanning tree identifier witheach socket, wherein the node identifier may be of a different valuethan the spanning tree identifier.